1. Field of the Invention
This invention relates to methods of continuously conveying strips of metal such as aluminum or of many other different materials in a floated manner.
2. Description of the Prior Art
When a strip of metal or other different material is passed through a heat-treatment apparatus, the strip is floated by a blowoff chamber which blows jets of gases against the strip from a plurality of blowoff openings provided through an upper surface of the chamber. The blowoff openings are arranged in such a number and manner that all the strips of up to maximum width to be treated are floated thereby.
The required capacity of a device for supplying the strip-floating gases to the blowoff chamber is determined as follows: ##EQU1## (where V is the blowoff speed of strip-floating gases; t, thickness of the strip; .alpha., coefficient; and B is width of the strip.)
That is, the smaller the width of the strip, the higher blowoff speed of strip-floating gases is required, and it is required for the device to have such a maximum supply rate as allows the gases to blow off through the blowoff chamber, from all the blowoff openings thereof, at the highest speed which causes the strip of smallest width to be floated.
With reference to FIG. 7 of the accompanying drawings, if the blowoff chamber of 2,029 mm. in width is required to blow gases at a supply rate of 500 Nm.sup.3 in order to float a strip of 1,829 mm. in width, the same chamber must blow off the gases at a supply rate of approximately 870 Nm.sup.3 per minute in order to float a strip of 610 mm. in width. Therefore, if the strips to be heat treated are of widths of 610 mm. to 1,829 mm., the device for supplying the strip-floating gases to the blowoff chamber is required to have a considerably great supply capacity, i.e., maximum supply rate of 870 Nm.sup.3 in order to float all the strips to be treated.